西南太平洋地区地震序列的特征

共搜集到１９８４￣１９９０年西南太平洋地区１２个板缘地震序列。多数地震序列的特征是：震中分布区域的长轴较长并且随主震震级和序列中强震次数而增加；震中分布区域的长、短轴长度的比值较高；地震序列的余震震源机制和主震的差异不大；震源深度下限超过地壳，可达７０ｋｍ以上。走滑型主震占的比例低，高倾角滑动面的走向既有与俯冲带走向平行的也有横切的，个别逆冲型地震的断层面走向横切俯冲带。它们显示出与板块俯冲带主体

FEATURES OF THE EARTHQUAKE SEQUENCES OF SOUTHWESTERN PACIFIC

Collected 12 examples of plate boundary earthquake sequences of Southwestern Pacific from 1984 to 1990. The features of most of the sequences are as below: the major axis of the epicenter area is longer,and increased with magnitude of the mainshock and mount of strong aftershocks,the ratio of the major axis to minor axis is larger; focal mechanism solutions of aftershocks are not significantly different to the solution of mainshock in a sequence; the deepest focus below the crust bottom can be at 70km or more.Percentage of strike-slip type mainshock is low. Some fault plane strikes of dip-slip type are parallel to the trend of subduction zone,and some are perpendicular to it.Fault planes strikes of a few reverse-slip type are perpendicular to the trend of subduction zone.They showed that different phenomena from fundamental feature of earthquake sequences in the plate subduction zone.